Question: How can the cloud standardize on a reference architecture when there are so many different ones?
In our work, clients often ask for a cloud reference architecture. They see it as a holy grail that will provide clear vision and help define their cloud strategies. In response to a recent client inquiry about a cloud hardware reference architecture that could be used to define a joint venture with another company, I realized that defining a cloud reference architecture as the same hardware platforms was the wrong way to look at the question. While I do agree a reference architecture is certainly a good starting point, it not something I would build an entire corporate cloud strategy around.
Reference architectures are supposed to be by their nature somewhat theoretical. Like the OSI model and the cloud stack model, they are artificial constructs or frameworks that can be used to create real systems. By themselves they tend to be so generic and broad that building an enterprise cloud based on a reference architecture without considerable work defining business objectives and system requirements would only be an exercise in frustration. For example, an enterprise cloud designed to be used for internal use as a more flexible development platform is a far different animal than an enterprise cloud planned to be used to support massively scalable customer facing applications.
After looking at a few available cloud reference models, a reference architecture means very different things depending on the agenda of the creator. A useful way to compare the perspectives of the various cloud reference architectures is to map them to the older and simpler Cloud Service Stack Model: IaaS, PaaS and SaaS. For example: both the NIST and its closely related IBM architecture are relatively generic and high level, but they both have an operational focus which closely matches the IaaS layer. The recently published RackSpace Private Cloud Reference Architecture while specific to OpenStack, also primarily has an operational/IaaS bias. Microsoft has defined the cloud not surprisingly more from a development platform/PaaS view, but it also has an IaaS flavored version based on Hyper-V. The HP and VMWare versions are more appropriate for companies building end to end applications, SaaS or otherwise.
In the end, a good cloud reference architecture should be robust enough to allow it to be used from a variety of different perspectives: business, operations, development and consumer. However, any company that is foolish enough to try to use a cloud reference architecture to create its strategy without the application of a rigorous amount of common sense and basic good business practices, is likely to be disappointed with the results.
About the Author
Beth Cohen is a Senior Cloud Architect for Cloud Technology Partners.
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